1. Field of the Invention
The present invention relates to a coating film peeling apparatus for resin material that removes the coating films on resin materials constituting defective vehicle bumpers or used bumpers on scrapped vehicles so that the resin materials can be recycled and processed into bumpers or resin parts for new vehicles to allow for reuse.
2. Description of the Related Art
Among traditional coating film peeling apparatus for resin materials used for bumpers, etc., one type of resin material peeling apparatus has been known wherein comprising: a peeling cylinder having a feed side on one end and release side on the other end; a peeling roll having multiple projections on the outer periphery and set in such a way as to form a space for a peeling process along the inner wall of the aforementioned peeling cylinder; a retaining plate set in such a way as to block the discharge port on the release side of the aforementioned peeling cylinder; and a pressure adjustment part that increases/decreases the push force of the aforementioned retaining plate and thereby adjusts the flow rate as well as internal pressure of the aforementioned peeling cylinder.
Patent Literature 1 describes a device wherein coarsely crushed pieces are fed between the peeling cylinder and peeling roll to peel the coating film on the surface of coarsely crushed pieces by rubbing off the coating film by the use of impact action and agitating action. This device simplifies the coating-film separation process, reduces cost, and also provides space-saving benefits, etc.
Patent Literature 2 describes a device that takes crushed material prepared by cleaning and crushing used bumpers and then drying the crushed pieces, wherein this crushed material is fed to said coating film peeling apparatus which is rotating in the same manner as a rice milling machine to peel coating film from the crushed material and thereby separate the coating film from the remaining recyclable base material [free from coating film]. This device can peel the coating film from the crushed material by agitating the crushed material under pressure and thereby shaving the coating film from the surface, which is beneficial in that all types of bumpers can be processed regardless of the type of coating film or method of coating.
Patent Literature 3 describes a coating film peeling apparatus comprising: a angular columnar body, in the peripheral wall of which coating film pass-through holes are formed through which to pass the coating film separated from crushed pieces; a coating film peeling part constituted by a peeling roll having projections and grooves formed on the columnar surface and also having gas injection holes through which to inject gas; a crushed pieces introduction part; a crushed pieces feed part; and a crushed pieces release part. This device can, through its projections and grooves provided on the columnar surface of the peeling roll, cut the coating film in advance to produce starting points from which to peel the coating film, and this mechanism further increases the peeling efficiency of coating film.
Patent Literature 4 describes a surface coating film peeling apparatus comprising: a peeling cylinder having a heating module; and a peeling roll housed inside the peeling cylinder wherein the peeling roll has multiple rubbing projections that are projecting from a roll axis in a spiral manner; wherein each of the aforementioned rubbing projections has a rubbing apex surface adjoining the inner surface of the peeling cylinder as well as an upward inclined front surface on the upstream side in the rotating direction of the peeling roll, to have waste resin material rubbed between the inner surface of the peeling cylinder and rubbing apex surface of the peeling roll. This device can give impact action to the waste resin material through rubbing, while keeping the generation of friction heat to a minimum, thereby permitting continuous processing.
However, the coating film peeling apparatus described in Patent Literatures 1, 2, 3 and 4 mentioned above have many coating film pass-through holes formed in the peripheral wall of the stripping cylinder through which to pass the coating film peeled from crushed pieces. One example of the shapes of these holes is shown in FIG. 6, where many long, thin elongated slits 102 are punched open in parallel in such a way that they run diagonally to the lengthwise direction of the peeling cylinder 101, while angular embossments 103 are provided to stand out between these elongated slits 102.
If such a peeling cylinder 101 having many coating film pass-through holes comprising elongated slits 102 and angular embossments 103 is used, then a micro-observation of the end face of an angular embossment 103 finds that the angular part has a sharp blade-like edge that would considerably shave the surface of the resin material from which to peel the coating film and bite into the recyclable material beyond the coating film layer of the resin material. In other words, the angular embossments 103 are provided for the purpose of improving the cutting action and, although they have no markedly adverse effects when the resin material is passed only once through the coating film peeling apparatus, an attempt to pass the resin material as much as four to five times through the coating film peeling apparatus with an intention to completely remove the coating film would cause the recyclable material to be excessively shaved and consequently the yield drops. In addition, the aforementioned elongated slits 102 also lower the yield in that if the resin material is a polygonal-shaped flat sheet with a thickness of 4 mm or less, the resin material comes out through the elongated slits 102 during the peeling process.
[Patent Literatures]
[Patent Literature 1] Japanese Patent Laid-open No. Hei 7-276364
[Patent Literature 2] Japanese Patent Laid-open No. Hei 11-58379
[Patent Literature 3] Japanese Patent Laid-open No. 2001-88128
[Patent Literature 4] Japanese Patent Laid-open No. 2005-96270